Starter not engaging?

[Tomahawk30]

Hey guys... I've been searching for similar threads, but haven't found exactly this issue described elsewhere. In a nutshell, the starter will spin, but doesn't engage the flywheel consistently. It was starting fine when I got it back from the shop that replaced the engine and did my paint and body work. After starting it a bunch of times to troubleshoot a carb / timing issue, it started just making a grinding sound about 9 times out of 10. Every so often it would engage fully and fire right up.

I initially suspected the flywheel, but it looks perfect. I pulled the starter and took it in to NAPA where they said it tested fine. When I was taking it back to reinstall, it rolled off the tailgate and busted the solenoid housing. I replaced the solenoid with a new one from NAPA, reinstalled, and got exactly the same issue again. The starter tries to engage, but it sounds like the starter isn't extending far enough to fully engage the flywheel gears. When I had the starter off, I could see the gears on the starter side were wore at the very leading edge. I tried shimming it, but when I do that it doesn't even touch the flywheel gears at all and sounds like it is just spinning free.

At this point, I suspect that the starter isn't engaging far enough into the flywheel gears. Is it possible that it would look good on a bench test, but not have enough force to engage properly into the flywheel gears? I don't know enough about the indicators of a failing starter to troubleshoot it very well. I might just pick up another starter tomorrow and give it a try, but thought I'd see if you guys have any input first....

[Tomahawk30]

Never mind.... Found some info over on the engine page.
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[b.eddy's72]

try to shim it

[cdowns]

i'd try sprayin the gear and shaft with thin cleaner lubricant before doin anything

sometimes a very slight amt of crap on the shaft will prevent the gear from popin out and engageing

[68gmsee]

Originally Posted by Tomahawk30

.......... Is it possible that it would look good on a bench test, but not have enough force to engage properly into the flywheel gears? ..........

Your choice of replacing the starter will probably fix the problem. Be sure and get the complete starter and solenoid. There's several factors involved with this failure (as mentioned above) but I've found out that in a case like yours it's probably the starter drive worn out.

[Tomahawk30]

Thanks guys. As suggested, I'll try cleaning it up a bit more, but I'm guessing it is the starter drive gear. It's certainly not the cleanest unit as it came off the previous engine that had a pretty severe oil leak at the rear main. Should have just bought the whole starter when I tried the new solenoid.
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[bronze 72 super]

Just a suggestion, but if you buy a replacement starter, try to buy a new one as opposed to a "rebuilt" one. Also try to stay away from imported ones. I had one break the cast iron nose on a big block motor once. This come from a chain parts store. Long store short, if you have the extra money invest in a good new one. Hey I live over in Rufus, right by the JOHN DAY DAM. If you ever have any problems with your truck, and happen to be in the area look me up. Just look for the "old Chevy trucks" out back. Mike.

[VetteVet]

If you look at the picture below you can see that the solenoid shaft connects to an arm that throws the starter bendix and gear into the flywheel teeth. It is a positive engagement that is spring loaded and if the solenoid is good then it will force the starter gear into the flywheel. Cleaning the gear shaft and lubing it is a good thing but I doubt it is your problem. Most likely the spring is weak or broken or the bendix is bad. The bendix is designed to slip when the gear binds or when the engine kicks back. And If you ever heard a starter continue to run after the engine has started then you will know the sound. I suspect that that is your problem unless you have a poor electrical connection or a bad ground.

I would remove the starter dust cover and disconnect the large battery cable from the solenoid. Then have someone hit the start switch and you can watch the gear and flywheel engagement. The starter won't turn because the main power is off but the solenoid will still work. You can also pry the starter gear out into the flywheel to check the clearance with a screwdriver That's how I did mine. Still take the negative battery of just in case if you do it this way. You should be able to get a 1/8 inch drill bit to slide in between the flywheel teeth and the starter gear if it''s shimmed correctly. Make sure you cover the positive cable end if you remove it from the solenoid or you might get arrested for welding without a helmet.LOL
Also don't hold the key in start for more than a few seconds as that's hard on the solenoid windings.

You should also check the flywheel all the way around for out of roundness or damage.

[Tomahawk30]

Originally Posted by bronze 72 super

Just a suggestion, but if you buy a replacement starter, try to buy a new one as opposed to a "rebuilt" one. Also try to stay away from imported ones. I had one break the cast iron nose on a big block motor once. This come from a chain parts store. Long store short, if you have the extra money invest in a good new one. Hey I live over in Rufus, right by the JOHN DAY DAM. If you ever have any problems with your truck, and happen to be in the area look me up. Just look for the "old Chevy trucks" out back. Mike.

Thanks Mike. I'm actually in John Day (the town) as opposed to John Day (the dam). Common misconception for anyone who has never had the "pleasure" of spending time in John Day the town. We are actually at the headwaters of the John Day river, and the dam is at the inflow of the John Day into the Columbia. Not a LONG drive, but not right next door either.

[Tomahawk30]

Originally Posted by VetteVet

If you look at the picture below you can see that the solenoid shaft connects to an arm that throws the starter bendix and gear into the flywheel teeth. It is a positive engagement that is spring loaded and if the solenoid is good then it will force the starter gear into the flywheel. Cleaning the gear shaft and lubing it is a good thing but I doubt it is your problem. Most likely the spring is weak or broken or the bendix is bad. The bendix is designed to slip when the gear binds or when the engine kicks back. And If you ever heard a starter continue to run after the engine has started then you will know the sound. I suspect that that is your problem unless you have a poor electrical connection or a bad ground.

I would remove the starter dust cover and disconnect the large battery cable from the solenoid. Then have someone hit the start switch and you can watch the gear and flywheel engagement. The starter won't turn because the main power is off but the solenoid will still work. You can also pry the starter gear out into the flywheel to check the clearance with a screwdriver That's how I did mine. Still take the negative battery of just in case if you do it this way. You should be able to get a 1/8 inch drill bit to slide in between the flywheel teeth and the starter gear if it''s shimmed correctly. Make sure you cover the positive cable end if you remove it from the solenoid or you might get arrested for welding without a helmet.LOL
Also don't hold the key in start for more than a few seconds as that's hard on the solenoid windings.

You should also check the flywheel all the way around for out of roundness or damage.

Thank you for this! I was trying to find that diagram. I knew I'd seen it somewhere... I did replace the solenoid yesterday with a new one and it was doing the same thing. COULD be a bad solenoid out of the box, but I'm leaning toward the bendix. I don't think it is a spacing or flywheel issue, as the teeth on the flywheel look perfect and it was starting just fine for the first month or so after I got it back.

[BarryB]

replace the starter drive and your problem will be fixed. Fixed a many of them with the same problems you described. for as cheap as a new starter is maybe just replace it.

[mac808]

I agree with 68gmsee and BarryB.

I had the same problem and thought my battery was just weak. After research on here and more than a handful of threads suggesting a particular starter from a place called DB Electrical, I checked it out and got one since I figured that I couldn't go wrong with the price.

You can do a quick search on this forum for 'DB Electrical' to check out what kind of problems others have experienced with their products and how their issues were solved.

Got it fast, installed it, and it now starts strong and easy like a champ. Might be worth checking them out.